This is a randomized, double-blind controlled trial of pulse loaded IV clomipramine (CMI), (day 1 150 mg; day 2 200 mg, days 3-6 zero) pulse loaded oral CMI and placebo (oral-plus-i.v.) in patients with treatment- unresponsive obsessive compulsive (OCD). Primary hypothesis: IV pulse loaded CMI will produce by day 6 a clinically meaningful improvement in OCR patients and this improvement will significantly exceed that produced by oral pulse-loaded CMI and placebo.